Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the first image in a sequence for a display screen or portionthereof with transitional graphical user interface showing our newdesign;

FIG. 2 is the second image thereof;

FIG. 3 is the third image thereof;

FIG. 4 is an enlarged view of the rounded square shape in the lowerright corner of FIG. 1, shown separately for clarity of illustration;

FIG. 5 is an enlarged view of the rounded square shape in the lowerright corner of FIG. 2, shown separately for clarity of illustration;and,

FIG. 6 is an enlarged view of the rounded square shape in the lowerright corner of FIG. 3, shown separately for clarity of illustration.

The outer perimeter illustrated in broken lines in the drawings depictsa display screen or portion thereof and forms no part of the claimeddesign. The remaining broken lines in the drawings depict portions ofthe graphical user interface that form no part of the claimed design.

The appearance of the transitional image sequentially transitionsbetween the images shown in FIGS. 1-3. The process or period in whichone image transitions to another image forms no part of the claimeddesign.

CLAIM The ornamental design for a display screen or portion thereof withtransitional graphical user interface, as shown and described.